JPH01253010A - Traffic control method for unmanned car conveyance system - Google Patents

Abstract

PURPOSE:To improve travel and traffic control efficiency by allowing an unmanned car to send back a specific answer signal with short signal length when receiving a polling signal from a central control office during its travel. CONSTITUTION:When the unmanned car CR is made to travel, the central control office 30 checks its interference with other cars, determines the position where the unmanned car CR is stopped or reduced in speed according to the check result, and sends out a stop or speed reduction command including the stop or speed reduction position to the unmanned CR. The unmanned car CR is stopped or reduced in speed only at the commanded stop or speed reduction position and sends back the answer signal with short signal length in response to polling during the car travel. Consequently, the stop time of the vehicle becomes short and one cycle of the polling is shortened, thereby performing efficiency communication control and travel control.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is an unmanned vehicle transportation system in which a plurality of unmanned vehicles travel along a predetermined travel route under polling control from a central control station, and is capable of efficiently preventing collisions between unmanned vehicles. Relates to a traffic control method designed to prevent this.

C. Prior Art] In a system in which a plurality of unmanned vehicles travel on a predetermined road, some kind of traffic control is required to prevent collisions between vehicles or improve work efficiency. This traffic control is generally divided into local control methods and central control methods.

In the local control system, ground equipment with a traffic light function is installed at each intersection, and the running and stopping of vehicles is controlled by this ground equipment.

The central control method performs control through polling communication between the central control station and the unmanned vehicle, and as shown in Figure 6, the vehicle CR travel route 1 (guidance lines are buried along travel route 1). is divided into a plurality of closed sections (blocks indicated by broken lines), and each closed section is given a corresponding representative position coordinate. A station line 2 is provided at the boundary between each blockade section so as to be orthogonal to the guide line 1, and the unmanned vehicle CR can determine its own position by detecting this station line 2 or using the on-board distance meter and direction meter. can be detected.

In such a central control system, the central control station cyclically communicates with each vehicle in a predetermined order (#1, #2, ... #n) by polling communication, as shown in FIG. do. On the other hand, on the unmanned vehicle side, when the vehicle enters a new blocked section or a new position coordinate (for example, Pl or P2 in Figure 6) that is a further subdivision of the blocked section, the vehicle is stopped and polled from the central control station. After that, when a polling signal is received, return data including position data and status data (indicating the vehicle's current status, such as stopped or starting running) as shown in Figure 8 is sent back to the central control station. . The central control station that receives this return data checks interference with other vehicles, and when it is the unmanned vehicle's turn to poll, it sends a GO double signal or a 5TOP signal to the unmanned vehicle based on the interference check results. Send it to the car. On the unmanned vehicle side, the vehicle is operated and operated based on the GO double signal or 5TOP signal sent from the central control station.
At the same time as controlling the stop, return data in the format shown in FIG. 8 is also transmitted to the central control station. The central control station repeatedly executes such control for each vehicle #1 to #n.

[Problem to be solved by the invention]

In this way, in the conventional central control system, vehicles were temporarily stopped each time they entered a new blocked section or location, which increased the time it took for vehicles to stop, making it difficult for them to reach their destination. The problem is that it takes time.

Furthermore, in the conventional central control system, the signal sent from the unmanned vehicle to the central control station always includes position data and status data, as shown in Figure 8. The communication time 1+1 (Fig. 7) becomes longer, and the polling period T (-(t + t
)Xn; Fig. 7) also becomes longer. This boring period T
determines the minimum length L of the occlusion section.

in, that is, L is In L −Txv v ; traveling speed of unmanned vehicle + li
It becomes n.

For this reason, in the conventional method, it is necessary to set a long blocked section, which deteriorates control efficiency.

This invention was made in view of the above circumstances, and provides a traffic control method for an unmanned vehicle transportation system that reduces waiting time and improves travel and control efficiency through efficient communication. .

[Means and operations for solving the problem] Therefore, in the present invention, the following communication procedure is repeatedly performed between the central control station and the unmanned vehicle.

(a) Upon receiving a polling signal from the central control station,
The unmanned vehicle returns position data indicating its current location and status data indicating the state of the vehicle.

(b) When driving an unmanned vehicle, one central control station sends a driving command including the destination location to the required unmanned vehicle,
Interference with other unmanned vehicles is determined from the travel course determined by this destination position and the received current position of the unmanned vehicle, and a position at which the unmanned vehicle is stopped or decelerated on the travel course is determined based on the determination result. , transmits a stop or deceleration command including these stop positions or deceleration positions to the unmanned vehicle.

(c) When the unmanned vehicle receives a stop or deceleration command from the central control station, it starts traveling along the travel course and continues until it reaches the stop or deceleration position instructed by the central control station. The vehicle runs while sending back a predetermined response signal with a short signal length in response to polling from the central control station.

(d) When the unmanned vehicle reaches the stop or deceleration position, it stops or decelerates and waits for polling from the central control station.

That is, when the unmanned vehicle receives a stop or deceleration command from the central control station in a polling cycle, the unmanned vehicle continues to travel without stopping or decelerating until it reaches the commanded stop or deceleration position. And during this run,
When polling is received from the central control station, the unmanned vehicle returns a predetermined response signal with a short signal length.

(Example) This invention will be described in detail below according to an example shown in the accompanying drawings.

Figure 2 shows a plan view of an unmanned vehicle, in which case a forklift is assumed. Unmanned car CR has 4 sides in front, back, left and right.
Pick-up coils 11 to 14 are provided, and the vehicle travels along the guide wire 1 by detecting the induced magnetic field of the guide wire 1 (see FIG. 6) buried in the travel path. Also, the station wire 2 (see FIG. 6) installed perpendicular to the guide wire 1 is detected by two pickup coils 15 and 16 provided at the front and rear.

FIG. 3 shows an example of the internal configuration of the unmanned vehicle CR and the central control station 30. The unmanned vehicle CR includes a communication device 21, a CPU 22,
Memory 23, distance meter 24, direction meter 25, position detection unit 26
, a travel control section 27, pickups 15 and 16, and the like.

The memory 23 stores Fro given from the central control station 30.
Route data (a sequence of blocked sections) indicating a travel route of an unmanned vehicle are stored in correspondence with m/lo data (data indicating a departure point and an arrival point). Therefore, C
When the PU 22 gives From/to data to the memory 23, one piece of predetermined route data corresponding to the given From/lo data is read out. When determining this route data, consideration is given to ensuring that the unmanned vehicle travels the shortest route. Further, the position detecting section 26 sequentially measures the current position of the user based on the outputs of the distance meter 24, the compass 25, and the pickup 15.degree. 16, and inputs this measured position to the CPU 22.

On the other hand, the central control station 30 includes a communication device 31, a controller 3
2, an interference check section 33, a route generation section 34, a route storage section 35, etc.

The route generation unit 34 has a route table that stores route data indicating the route of the unmanned vehicle separately from the From/lo data, and when the From/lo data and the vehicle number code are given by the operator, the From/lo
The route data corresponding to the data is read from the route table, and the route data and vehicle number code are manually entered into the interference check section 33, and these data are stored in the route storage section 35.

In this way, two pieces of route data indicating the arrangement of blocked sections are stored in the route storage unit 35 for each vehicle. Further, when a new route is set by the route generating section 34, the interference checking section 33 checks the area that interferes with the route of another vehicle, and determines the vehicle to be stopped and its stopping position based on the result of this check. Note that vehicle interference includes: (1) a collision at an intersection, (2) a head-on collision, and (2) a rear-end collision, and an interference check is performed that takes these into consideration.

FIG. 4 shows an example of the format of signals transmitted and received between the central control station 30 and the unmanned vehicle CR.

The signal sent from the central control station 30 to the unmanned vehicle 20 includes:
As shown in FIG. 4(a), the polling signal, From
There is a /lo signal and a command signal. The polling signal consists of 1 byte and is used for polling when no special instructions are issued.

The From/lo signal is composed of 3 bytes, and data indicating the starting point and destination is added thereto as described above. A command signal is a command signal that causes an unmanned vehicle to perform operations such as stopping or decelerating, and a code indicating a stop command, deceleration command, etc. is entered in the first "command code", and a code indicating a stop command, deceleration command, etc. is inserted in the "position data" field. Data indicating the stop position and deceleration position is entered there.

The signal sent from the unmanned vehicle CR to the central control station 30 includes:
As shown in FIG. 4(b), there are an ACK signal, a position signal, and a status signal, each of which is 1 byte,
It consists of 3 bytes and 2 bytes. The ACK signal will be described in detail later, but it is simply for responding to polling from the central control station 30, and is composed of one byte with a short signal length. The position signal is used to send position data, and status data indicating the current state of the unmanned vehicle is added to the rear of the position signal. Next, the status signal is a signal used when only status data is sent, and is normally used as a response signal to the From/lo signal.

The specific operation will be explained below with reference to FIGS. 1 and 5.

Assume that on a traveling path as shown in FIG. 5, car #1 is waiting at the origin, and cars #2 and #3 are traveling at the positions shown. Now, #1 is sent to the central control station 30 by the operator.
Suppose that a car is given the command to load cargo at trestle station ■ and unload this cargo at trestle station ■.
Consider the case where car #1 is driven to trestle station ■.

First, the central control station 30 sends a polling signal to car #1 (time 1+ in Figure 1). Upon receiving this polling signal, the CPU 22 of car #1 obtains the current position (block Xi in this case) based on the detection output of the position detection unit 26,
A position signal (fourth
(see figure (b))) is returned to the central control station 30 (time 1+ in figure 1).

The central control station 30, which received this position signal, next sends an Fr.
The om/lo signal is transmitted to car #1 at the next polling cycle of car #1 (time 1+ in Figure 1). Along with this, the controller 32 of the central control station 30
The From/lo data corresponding to B2 is sent to the route generation unit 3.
4, reads out the corresponding route data, and inputs it to the route storage section 35 and the interference check section 33. In this case, the route data read from the route generation unit 34 is X1→X2→X3→X4-X5-X6-X7-
X8-Y33→Y34-Y35→Y36 shout X29→Y3
Suppose that it is 7.

The interference check section 34 selects points where there is a possibility of interference by comparing and collating the human-operated route data regarding car No. 1 with the route data regarding other vehicles. In this case, it is assumed that it is determined by the interference check that there is a possibility of interference at intersections Z1 and Z2. The controller 32 determines the vehicles to be stopped and their stopping positions based on (1) the distance from the intersection to each vehicle, (2) a preset priority order of the vehicles, etc. In this case, assume that car #1 is stopped at block X5 before intersection Z1 and block Y36 before intersection Z2.

On the other hand, the CPU 22 of the unmanned vehicle #1 that has received the From/lo signal inputs the starting point data and destination data included in the From/lo signal into the memory 23, thereby creating a route corresponding to the starting point and destination. Read data. This route data is exactly the same as the route data determined by the central control station 30, and the CP of unmanned vehicle #1 is
U22 can automatically travel along the route corresponding to the route data by controlling the travel control unit 27 while feeding back the detection output of the position detection unit 26. Along with this, unmanned vehicle #1
In response to the signal, a status signal (see FIG. 4(b)) indicating reception of the From/lo signal is sent back to the central control station 30 (time t4).

Upon receiving this status signal, the central control station 30 sends a command signal (see FIG. 4(a)) indicating a stop command to #1.
It is transmitted to unmanned car #1 at the next polling cycle regarding the car (time ts in FIG. 1).

This stop command is appended with position data indicating the first stop position, that is, block X5, determined in the manner described above.

When the unmanned vehicle receives this stop command (stop at block X5), it sends an ACK signal back to the central control station 30, and at this point the vehicle starts running (time ts in Figure 1).
. Thereafter, the unmanned vehicle #l continues to drive without stopping until it reaches block X5, and each time a polling signal is sent from the central control station 30, it returns an ACK signal (see Figure t7~t1o)
.

When the unmanned vehicle #1 reaches block X5, it stops and waits for polling from the central control station 30.

After that, upon receiving a polling signal from the central control station 30 (time t1□ in Figure 1), unmanned vehicle #1 moves to block X5.
A status signal indicating that the aircraft is waiting for air traffic control (Fig. 4)
b)) is returned to the central control station 30 (at time t in Figure 1).
12).

The central control station 30 waits for car #2 to pass intersection Z by polling car #2, and when it recognizes the passing, it polls car #1 at the next polling cycle for car #1. A stop signal to stop at the second stop position (block Y36 in this case) is sent (time t13 in FIG. 1).

When the unmanned vehicle receives this stop command (stop at block Y36), it sends an ACK signal back to the central control station 30 and resumes running the vehicle (time t14 in FIG. 1). Thereafter, unmanned vehicle #1 travels without stopping until it reaches block Y36, and returns an ACK signal in response to polling from central control station 30 in the same manner as described above.

Then, when unmanned vehicle #1 reaches block Y36, it is stopped. Thereafter, in the same manner as described above, unmanned vehicle #1 responds to polling from central control station 30 and returns a status signal indicating that it is waiting for control at block Y36.

The central control station 30 waits for the #3 car to pass by polling the #3 car, and when it recognizes the passage, sends a stop signal to the #1 car to stop at block Y37. As a result, unmanned vehicle #1 changes direction via block X29, travels to block Y37, and stops there.

In this embodiment, the unmanned vehicle CR is operated by the central control station 3.
When a stop command including a stop position is sent from 0, the vehicle runs without stopping until it reaches the commanded stop position, and during this time, the signal length is adjusted in response to polling from the central control station. Short (does not include location data) A
Since the CK signal is sent back, the waiting time of the vehicle is reduced compared to the conventional method, which pauses the vehicle every time it enters a new block and always sends back a signal containing position data and status data. This reduces the amount of traffic and allows for efficient communication and travel.

In the above embodiment, the vehicle is stopped, but the vehicle may be caused to travel at a reduced speed, or may be controlled by a combination of deceleration and stopping.

〔Effect of the invention〕

As explained above, according to the present invention, when an unmanned vehicle is run, the central control station checks for interference with other vehicles, determines the position to stop or decelerate the unmanned vehicle based on the result of the check, and Sending a stop or deceleration command including a stop or deceleration position to the unmanned vehicle, the unmanned vehicle stopping or decelerating the vehicle only at the commanded stop or deceleration position;
In addition, in response to polling while the vehicle is running, a response signal with a short signal length is returned, which shortens the vehicle stop time and shortens one cycle of polling, resulting in more efficient communication control and driving control. You will be able to do it.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a signal transmission procedure in an embodiment of the present invention, Fig. 2 is a plan view showing the arrangement of pickup coils of an unmanned vehicle, and Fig. 3 is an example of a device configuration for carrying out the invention. FIG. 4 is a diagram showing an example of the format of a transmission signal, FIG. 5 is a diagram conceptually showing an example of an unmanned vehicle transport path, and FIG. 6 is a diagram showing the arrangement of guide lines of the unmanned vehicle transport path, etc. FIG. 7 is a diagram showing a conventional signal transmission procedure, and FIG. 8 is a diagram showing a conventional transmission signal format. 1... Guide line, 2... Station line, CR...
Unmanned vehicle, 11-16...Pickup coil, 22.
...CPU, 23...Memory, 26...Position detection section, 30...Central control station, 32...Controller, 3
3... Interference check section, 34... Route generation section, 3
5...Route storage section. Figure 3 Figure 6

Claims (1)

[Claims] A plurality of unmanned vehicles are driven on a predetermined running route, and a central control station is provided to centrally manage the plurality of unmanned vehicles. An unmanned vehicle transportation system that controls traffic of unmanned vehicles by polling communication, characterized in that each unmanned vehicle is controlled by repeatedly performing the following communication procedure between the central control station and the unmanned vehicles. A traffic control method for an unmanned vehicle transportation system. (a) Upon receiving a polling signal from the central control station,
The unmanned vehicle returns location data indicating its current location and status data indicating the state of the vehicle. (b) When driving an unmanned vehicle, the central control station transmits a driving command including the destination position to the required unmanned vehicle, and also selects other unmanned vehicles from the driving course determined by this destination position and the received current position of the unmanned vehicle. Determine interference with cars,
Based on the determination result, a position at which the unmanned vehicle is to be stopped or decelerated on the traveling course is determined, and a stop or deceleration command including these stopping positions or deceleration positions is transmitted to the unmanned vehicle. (c) When the unmanned vehicle receives a stop or deceleration command from the central control station, it starts traveling along the travel course and continues until it reaches the stop or deceleration position instructed by the central control station. The vehicle runs while sending back a predetermined response signal with a short signal length in response to polling from the central control station. (d) When the unmanned vehicle reaches the stop or deceleration position, it stops or decelerates and waits for polling from the central control station.